We live in the Milky Way galaxy; a spiral galaxy. Our solar system resides roughly 25,000 light years from the massive black hole at the center of it all. The Milky Way is about 12 billion years old, and is 100,000 light years in diameter. Our very own star, the Sun, is only one of 100 billion stars scattered throughout the Milky Way. The size of our galaxy is mind boggling; the amount of stars it contains is equally mind boggling. But is it the biggest there is?
The Milky Way’s closest neighbor galaxy is Andromeda. Andromeda is another spiral galaxy nestled in the cosmos 2.5 million light years from us. Unfortunately, we are not the big brother in our cosmic neighborhood, because Andromeda is really big! How big, you might ask. Well, twice the size of our own Milky Way. That’s right! Andromeda is 200,000 light years in diameter and contains 1 trillion stars; that’s TRILLION… with a ‘T’, not a ‘B’. By comparison, Andromeda is much more dense with stars than the Milky Way is. We have 5 million stars per 5,000 light years, and Andromeda has 25 million stars per 5,000 light years.
Pretty crazy numbers if you ask me. But just wait, it gets crazier!
Far off in the distance, and I mean FAR OFF in the distance, resides a galaxy that is so big, and so massive, that it contains 15 trillion stars. The galaxy known as NGC 262 is just over 200 million light years from us. It is also a spiral galaxy with a diameter of 1.3 million light years. It’s enormous size makes NGC 262 about 10 times bigger than most spiral galaxies. It’s star density is 57.7 million stars per 5,000 light years. Wow! But is it the biggest?
No! NGC 262 is not the biggest galaxy that we have seen. In fact, NGC 262 pales in comparison to IC 1101. This galaxy, IC 1101 is an elliptical galaxy that rests about 1 billion light years from us, and holds within it 100 TRILLION stars! Man almighty that is a big number! It can do this, in part, because of its unimaginable size; IC 1101 is 6 million light years in diameter. It is six times bigger than the previous galaxy I mentioned, and 60 times bigger than our own Milky Way. The star density for IC 1101 is 83 million stars per 5,000 light years.
So, to answer my original question: is the Milky Way galaxy the biggest there is? The answer is absolutely not! I just mentioned a few larger ones, but there are more. Different shapes, different sizes, different everything, is part of what makes our universe a truly amazing place.